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ECAT Chemistry Chemical Equilibrium Test Online

Maan AliLast Updated: April 19, 2025

Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

Total Questions:	63
Time Allowed:	30 Minutes
Total Marks:	63
How to Attempt Test:	Please choose the right Option in MCQ-type question.
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ECAT Chemistry Chemical Equilibrium Test

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Page 1 of 3

Chemistry

1. In reversible reactions, if the forward reaction occur very fast then reactant (s) is (are) __________

At very high temperature

Solids

Unstable

Stable

2. Le-Chatelier’s principle is sometime known as

All of these

Law of mobile equilibrium

Law of active mass

Law of mass action

3. What can affect the magnitude of equilibrium constant Kp of a reversible gaseous reaction

Temperature

Pressure

Catalyst

None of these

4. AgCl dissolved with cone (2 x 10¯²) Ksp will be

3.6 x 10¯⁶

3.6 x 10¯⁵

4 x 10¯⁴

7.2 x 10¯⁶

5. Conjugate base of a very weak acid is

Weak base

Do not ionize

Salt

Strong base

6. An equilibrium constant of 10¯⁴ for a reaction means that the reaction is

One that is unfavourable and will not have very much product at equilibrium

The equilibrium constant only relates to the speed of a reaction and not to the amount of product formed

One that will have 50% product and 50% reactant at equilibrium

One that is very favorable and will have mostly product at equilibrium

7. Reaction which proceed in both the directions is called

Irreversible

Spontaneous

Non spontaneous

Reversible

8. In which of the following cases, the reaction goes farthest to completion?

K = 10⁰

K = 10

K = 10³

K = 10¯²

9. PH of human blood is

7.00

7.50

7.80

7.35

10. Which of the following gives a basic buffer?

NH₄OH + NH₄Cl

NaOH + CH₃ COONa

NaOH + NaCl

NaCl + CH₃ COOH

11. pH of milk is

6.5

7.5

12. For a reaction H₂ + I₂ ⇌ 2HI at 721 K, the value of equilibrium constant is 50. If 0.5 moles each of H₂ and I₂ is added to the system the value of equilibrium constant will be

0.02

0.2

13. If the value of kc is very low then the forward reaction will occur __________

Slowly

Randomly

Fast

Moderately

14. Kc > Products / Reactants favours

Reaction completed

Backward reaction

Forward reaction

Equilibrium

15. In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled then the equilibrium constant will

Becomes one fourth

Remains the same

Be halved

Also be doubled

16. Addition of CH3COOH and CH3COONa gives in water

Acidic buffer solution

Buffer solution

Standard solution

Both b and c

17. Who studied the effect of temperature on equilibrium?

Lewis

Arrhenius

Van der Waal

Vant Hoff

18. The factor which changes equilibrium constant o the reaction A₂(g) + B₂(g) → 2 AB(g) is

Amounts of A₂ and B₂

Catalyst

Temperature

Total pressure

19. When H₂ and I₂ are mixed and equilibrium is attained, then

None of these

Amount of HI formed is equal to the amount of H₂ dissociated

The reaction stops completely

HI dissociation stops

20. When rate of forward reaction is equal to rate of backward reaction, then the equilibrium established is called

Static equilibrium

Dynamic equilibrium

None of all

Chemical equilibrium

21. Which statements are correct for a reaction at equilibrium?
(I) The forward and reverse reactions both continue
(II) The rates of the forward and reverse reactions are equal
(III) The concentrations of reactants and products are equal

I and II only

II and III only

I, II and III only

I and III only

22. Which pH is considered as basic?

23. The relationship between Kp and Kc is give by

Kp = Kc (RT)∆n

Kc = Kp (RT)∆n

Kp = Kc (RT)-∆n

Kp = Kc (RT)∆

24. Idea of PH and POH was put forward by

Gibbs

Sorenson

Einstein

Chadwiick

25. Which set of solutes will form a buffer when dissolved in water to make 1 litter of solution?

0.0002M HCl

0.4 mole of NH3 with 0.2 mole of HCl

0.4 mole of CH3COOH with 0.4 mole of NaOH

0.2 mole of NaCl with 0.2 mole of HNO3

Page 2 of 3

26. At certain temperature, 50% of HI is dissociated into H₂ and I₂ the equilibrium constant is

0.25

0.5

3.0

1.0

27. The rate of chemical reaction is directly proportional to the active mass of reactant this statement is known as ___________

Law of Equilibrium

None of these

Law of Mass Action

Law of reaction

28. In an exothermic reaction, a 10° rise in temperature will

Produce some increase in Kc

Double the value of Kc

Decrease the value of equilibrium constant

Not produce any change in Kc

29. Which one of the following is a buffer solution?

Glue

Blood

Solution of CuSO4

Brine

30. In a chemical reaction N₂ + 3H₂ ⇌ 2NH₃ at equilibrium point

Equal volumes of N₂ and H₂ are reacting

Equal masses of N₂ and H₂ are reacting

The reaction has stopped

The same amount of ammonia is formed as is decomposed into N₂ and H₂

31. For the reaction 2A(g) + B(g) ⇌ 3C(g) + D(g) two moles each of A and B were taken into a flask. The following must always be true when the system attained equilibrium

[B] = [C]

[A] < [B]

[A] > [C]

[A] = [B]

32. Synthesis of ammonia by Habor process is an example of ___________

Constant Reaction

Reversible Reaction

Decomposition Reaction

Irreversible Reaction

33. The product of [0H¯][H⁺] at 25C° is

10¯¹⁰

10¯¹⁴

10¹⁰

10¯²⁰

34. A buffer solution can be prepared by mixing

A strong acid and weak base

A weak acid and weak base

A strong acid and its salt

A weak base and its salt with strong acid

35. The equilibrium constant in a reversible chemical reaction at a given temperature

Is not characteristic of the reaction

Depends on the concentration of one of the products at equilibrium

Depends on the initial concentration of the reactants

Does not depend on the initial concentrations of reactants

36. In an exothermic reversible reaction increase in temp shifts the equilibrium to

Product side

Fluctuate

Reactant side

Remains unchanged

37. The equilibrium will shift towards right by increasing ___________ of reactants

Concentration

Temperature

Pressure

Impurity

38. If rate of concentration of reaction is equal to rate of concentration of products in reversible reaction the __________

Equilibrium will established

Reaction goes backward

Reaction goes forward

Reaction stops after some time

39. Water and ice are in equilibrium at 0C° and pressure is applied at this stage, then

Water evaporates

More water is formed

More ice is formed

Equilibrium is not disturbed

40. If a buffer solution of higher PH than seven is to be made we use

Weak base and its salt with a strong acid

Weak acid and its salt with a strong base

Strong acid and strong base

Weak acid and strong base

41. A chemical reaction A ⇌ B is said to be in equilibrium when

Conversion of A to B is only 50% complete

The rate of transformation of A to B is just equal to rate of transformation of B to A in the system.

Only 10% conversion of A to B has taken place

Complete conversion of A to B has taken place

42. When ever a week a base is dissolved in water, it gives its conjugate acid similarly a weal acid in water products its conjugate base. The conjugate acid base pair is stated by

Common on effect

Law of mass action

Lowery Bronsted concept

Le – Chatelier’s principle

43. For equilibrium 2NO₂(g) ⇌ N₂O₄(g) + 14.6 kcal increase of temperature would

Favour the decomposition of N₂O₄

Stop the reaction

Favour the formation of N₂O₄

Not alter the equilibrium

44. The state of equilibrium refers to

State or rest

Stationary state

State of inertness

Dynamic state

45. When sparingly soluble salt is in equilibrium with molar concentration of its oppositely charged ion when the product is called

Dissociation constant

Common ion effect

Solubility product

Dissociation constant for an acid

46. The rate at which a substance reacts is directly proportional to its active mass and the rate of reaction is directly proportional to the product of the active mass of reacting substances is known as

Law of conservation of energy

Law of mass action

Le – Chatelier’s principle

None of all

47. When pressure is applied to the given equilibrium ice water which of the following will happen

Equilibrium will not be disturbed

More ice will be formed

Water will formed

More water will be formed

48. Which of the following factors will favour the reverse reaction in a chemical equilibrium?

None of these

Increase in concentration of one of the products

Removal of one of the products regularly

Increase in concentration of one of the reactants

49. When pressure is applied to the equilibrium system Ice ⇌ Water? Which of the following phenomenon will happen?

More water will be formed

Equilibrium will not be formed

More ice will be formed

Water will evaporate

50. Which of the following aqeous solution will be basic?

Na₂CO₃

Fecl₃₋

Na₂SO₄

NaCl

Page 3 of 3

51. Solubility of any salt can be determined from

Ksp

52. Temperature for preparation of SO₃ is

400 °C

600 °C

200 °C

400 – 500 °C

53. What is the relationship between kp and kc?

Kc - kp (RT)∆n

kp = kc (RT)-∆n

kp = kc (RT)∆n

kc = kp (P)-∆n

54. The reaction 2SO₂ + 2O₂ ⇌ 2SO will be favoured by

High temperature and low pressure

Low temperature and low pressure

High temperature and high pressure

Low temperature and high pressure

55. In reversible reaction the changes in forward and backward reaction occur _________

Individually

Simultaneously

None

Both a and b

56. At start of reaction, concentration of reactants are on

Optimum side

Higher side

Lower side

Constant

57. Chemical equilibrium is referred to as dynamic because, at equilibrium, the

Equilibrium constant changes

Reactants and products keep reacting

Concentrations of the reactants and products continue to change

Rates of the forward and backward reactions change

58. A basic Buffer solution can be prepared by mixing

Weak base and its salt with strong acid

Weak acid and its slat with strong base

Strong acid and its slat wit weak base

Strong base and its salt with weak acid

59. Units of Kc is

Moles¯² dm⁺⁶

Kc may or may not have units

Moles⁺² dm¯⁶

Moles² dm⁺⁶

60. Preparation of buffer solution can be done by mixing

Weak acid and its salt with weak base

Strong acid and its salt with weak base

Strong base and its salt with weak acid

Weak base and its salt with strong acid

61. Which of the following is more acidic?

Bananas

Apples

Lemons

Bread

62. Two moles of HI was heated in a sealed tube at 440°C till the equilibrium was reached. HI was found to be 22% decomposed. The equilibrium constant for dissociation is

1.99

0.0199

0.0796

0.282

63. By the addition of base in water pH will be

Less than 7

More than 7

No effect

Equal to 7

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Maan AliLast Updated: April 19, 2025

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ECAT Chemistry Chemical Equilibrium Test Online

Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

ECAT Chemistry Chemical Equilibrium Test

Chemistry

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Maan Ali

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Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

ECAT Chemistry Chemical Equilibrium Test

Chemistry

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